. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PROTAMINHS IN A HOLOCFPHALAN FISH 191 A225 5 X (N - - A ,'' " Q8 - ^s 06 - ,-' \ Q4 - \ . ' -0/4 O2 - -\A- 4 /\ 1 -^ 00 - I VJ ^"^^__ I II 1 1 1 1 1 i r — ' — • ' T 1 1 0 40 80 120 160 200 220 (Nad) fraction number R3 ~^ mo h I II 100 100 24 6 8 10 12 14 16 16 20 22. R3 v mo V a b c d e f 9 Figure 3. Chromatographic purification of R3 and mO proteins. A. CM-cellulose chromatography of proteins extracted from sperm nuclei without previous reduction. Molanty of NaCl is shown on righthand
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PROTAMINHS IN A HOLOCFPHALAN FISH 191 A225 5 X (N - - A ,'' " Q8 - ^s 06 - ,-' \ Q4 - \ . ' -0/4 O2 - -\A- 4 /\ 1 -^ 00 - I VJ ^"^^__ I II 1 1 1 1 1 i r — ' — • ' T 1 1 0 40 80 120 160 200 220 (Nad) fraction number R3 ~^ mo h I II 100 100 24 6 8 10 12 14 16 16 20 22. R3 v mo V a b c d e f 9 Figure 3. Chromatographic purification of R3 and mO proteins. A. CM-cellulose chromatography of proteins extracted from sperm nuclei without previous reduction. Molanty of NaCl is shown on righthand vertical axis. Fraction II contains the purified protein R3 (see electrophoretic control on right). Lane h shows histones from unripe testes of Hyilrnlagits cullici B. HPLC of protein contained in peak I from panel A. Fractions 3 and 4 contain R3 protein and fraction 8 contains mO protein. not be homologous. In fact, scylliorhinines Zl and Z2 may not be homologous to each other. In spite of pos- sessing comparable amino acid compositions, Zl and Z2 do not have similar sequences (Chevaillier, 1991). The cysteine content is also significantly different: whereas scylliorhinines are very rich in this amino acid residue, protamines Rl and R2 from ratfish (and also the minor protamines ml, m2, and m3) have a poor content of cys- teine. To verify the low content of cysteine in ratfish sperm basic proteins, we applied the method described by Creighton (1980), which relies on the charge differences introduced by specific chemical modification of the amino acid. In Cys residues, the reaction of the thiol group with iodoacetic acid introduces a new acidic group, whereas reaction with neutral iodoacetamide does not change the net charge. Thus, the method consists of adding varying ratios of iodoacetamide to iodoacetate to portions of the protein to generate a com-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabil
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
